Mumbai University > Electronics Engineering > Sem 8 > MEMS Technology

Marks: 10M

• The Airbag is a very common automobile safety device.
• Airbags are inflated by gas produced in a chemical reaction. Gas inflates the airbag with velocities of up to 320km/h. The entire process happens in 20-30 milliseconds.
• It consists of the airbag cushion, a flexible fabric bag, inflation module and impact sensor. The purpose of the airbag is to provide the occupants a soft cushioning and restraint during a crash event. It can reduce injuries between the flailing occupant and the interior of the vehicle.
• Automotive airbag sensors are available in the form of a single chip containing a smart sensor or accelerometer, which measures the rapid deceleration of a vehicle on hitting the object.
• This single chip module is housed within the steering wheel.
• When an accident occurs, the sensors detect the collision and detect the rate of deceleration.
• Then this crucial information or signal is sent to Electronic Control Unit or ECU.
• The ECU determines the severity of the impact based on input data.
• If ECU determines that an airbag deployment is necessary, it sends a signal to initiate the airbag inflators.
• The inflator is activated through the igniter causing a chemical reaction that emits gas, resulting in deployment of the airbag cushion.

• Accelerometer sensor is used in airbag systems. The fabrication process for the same is as follows-